Method for treating mucositis, method for treating tumor, and
pharmaceutical combination

ABSTRACT

Disclosed is a method for treating tumor in a mammalian subject, which comprises administering a combination of (a) an anti-tumor agent and (b) a fatty acid derivative represented by the formula (I): 
     
       
         
         
             
             
         
       
     
     to the subject in need thereof. The application also discloses a method for treating damages, especially gastrointestinal damages including mucositis such as stomatitis induced by an anti-tumor agent, wherein the method comprises administering a fatty acid derivative of formula (I) to the subject who is receiving the anti-tumor agent.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of application Ser. No. 14/739,242filed Jun. 15, 2015, which is a divisional of application Ser. No.12/882,794 filed Sep. 15, 2010, which issued as U.S. Pat. No. 9,084,815on Jul. 21, 2015, and which claims priority from U.S. ProvisionalApplication No. 61/243,019 filed Sep. 16, 2009, the contents of all ofwhich are herein incorporated by reference.

TECHNICAL FIELD

The present invention relates to a pharmaceutical combination of ananti-tumor agent and a fatty acid derivative for treating tumor in amammalian subject. The present invention also relates to a method fortreating tumor in a mammalian subject. The present invention furtherrelates to a composition and a method for treating damages, especiallygastrointestinal damages including mucositis such as stomatitis inducedby an anti-tumor agent.

BACKGROUND ART

Neoplastic diseases are recognized throughout the world as being seriousand often life-threatening conditions. These neoplastic diseases havebeen and continue to be the subject of worldwide research effortsdirected toward the identification of therapeutic agents which areeffective in the treatment of patients suffering therefrom.

There are a variety of anti-tumor agents to treat neoplastic diseases.For example, 5-fluorouracil (hereinafter referred to as “5-FU”) is anantimetabolite having a structure of pyrimidine analog, which is used asa drug in the treatment of neoplastic diseases. Its principal uses arein gastrointestinal cancer such as gastric cancer, colon cancer, rectalcancer and pancreatic cancer. Other uses are for example, in hepaticcancer, breast cancer, uterine cancer and ovarian cancer. Thechemotherapy agent 5-FU acts principally as a thymidylate synthaseinhibitor. Thymidylate synthase inhibitors include 5-FU, Capecitabine,Tegafur, Carmofur, Floxuridine, and so on. Tegafur is known to release5-FU when activated in the living body. 5-FU is known to have theserious problem that the prolonged presence of 5-FU in the living bodycauses damages in the digestive organs such as oral cavity andintestine. Patients receiving continuous intravenous infusion of 5-FUalone often experience those damages.

Cisplatin, cisplatinum, or cis-diamminedichloroplatinum(II) (CDDP) is aplatinum-based chemotherapy drug used to treat various types of cancers,including testicular tumor, bladder cancer, prostatic cancer, ovariancancer, non-small cell lung cancer, esophageal carcinoma, cervicalcancer, gastric cancer, osteosarcoma, lymphomas, and germ cell tumors.It was the first member of a class of anti-cancer drugs which now alsoincludes carboplatin, nedaplatin and oxaliplatin. These platinumcomplexes react in vivo, bind to and cause crosslinking of DNA whichultimately triggers apoptosis (programmed cell death).

In general, severe side effects of those anti-tumor agents limit thedose escalation and prevent from achieving higher therapeutic effects.

In order to improve the therapeutic effect, some combinations of pluraldrugs which have different mechanisms and different side effects areproposed. However, more potent drugs and therapeutic method are stillstrongly desired such that the survival time of cancer patients isfurther prolonged and that the QOL of cancer patients is improved.

Prostaglandins (hereinafter, referred to as PG(s)) are fatty acidderivatives, members of class of organic carboxylic acids, which arecontained in tissues or organs of human or other mammals, and exhibit awide range of physiological activity. PGs found in nature (primary PGs)generally have a prostanoic acid skeleton as shown in the formula (A):

On the other hand, some of synthetic analogues of primary PGs havemodified skeletons. The primary PGs are classified into PGAs, PGBs,PGCs, PGDs, PGEs, PGFs, PGGs, PGHs, PGIs and PGJs according to thestructure of the five-membered ring moiety, and further classified intothe following three types by the number and position of the unsaturatedbond at the carbon chain moiety:

Subscript 1: 13,14-unsaturated-15-OH

Subscript 2: 5,6- and 13,14-diunsaturated-15-OH

Subscript 3: 5,6-, 13,14-, and 17,18-triunsaturated-15-OH.

Further, the PGFs are classified, according to the configuration of thehydroxyl group at the 9-position, into α type (the hydroxyl group is ofan α-configuration) and β type (the hydroxyl group is of aβ-configuration).

PGs are known to have various pharmacological and physiologicalactivities, for example, vasodilatation, inducing of inflammation,platelet aggregation, stimulating uterine muscle, stimulating intestinalmuscle, anti-ulcer effect and the like.

Some 15-keto (i.e., having oxo at the 15-position instead ofhydroxy)-PGs and 13,14-dihydro (i.e., having single bond between the 13and 14-position)-15-keto-PGs are fatty acid derivatives known as thesubstances naturally produced by the action of enzymes during themetabolism of primary PGs.

U.S. Patent application publication No. 2006/0281818 to Ueno et al.describes that a specific prostaglandin compound has a significanteffect on a conformational change in the TJs that results in recovery ofgastrointestinal mucosal barrier function.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a method or medicamentfor achieving higher therapeutic effects against tumor by reducing toxicside effects induced by an anti-tumor agent.

Another object of the present invention is to provide a method ormedicament for treating a disease or condition induced by an anti-tumoragent.

A further object of the present invention is to provide a method ormedicament for treating mucositis.

The present invention relates to a pharmaceutical combinationcomprising:

(a) a pharmaceutically effective amount of an anti-tumor agent selectedfrom the group consisting of an alkylating agent, an antimetabolite, anantibiotic, a plant alkaloid, a molecular targeting drug, a hormone, aplatinum complex, an antisense, an antibody and RNAi, and(b) a pharmaceutically effective amount of a fatty acid derivativerepresented by the formula (I):

wherein L, M and N are hydrogen, hydroxy, halogen, lower alkyl,hydroxy(lower)alkyl, lower alkanoyloxy or oxo, wherein at least one of Land M is a group other than hydrogen, and the five-membered ring mayhave at least one double bond;

A is —CH₃, or —CH₂OH, —COCH₂OH, —COOH or a functional derivativethereof;

B is single bond, —CH₂—CH₂—, —CH═CH—, —C≡C—, —CH₂—CH₂—CH₂—, —CH═CH—CH₂—,—CH₂—CH═CH—, —C≡C—CH₂— or —CH₂—C≡C—;

Z is

or single bond

wherein R₄ and R₅ are hydrogen, hydroxy, halogen, lower alkyl, loweralkoxy or hydroxy(lower)alkyl, wherein R₄ and R₅ are not hydroxy andlower alkoxy at the same time;

R₁ is a saturated or unsaturated bivalent lower or medium aliphatichydrocarbon residue, which is unsubstituted or substituted with halogen,alkyl, hydroxy, oxo, aryl or heterocyclic group, and at least one ofcarbon atom in the aliphatic hydrocarbon is optionally substituted byoxygen, nitrogen or sulfur; and

Ra is a saturated or unsaturated lower or medium aliphatic hydrocarbonresidue, which is unsubstituted or substituted with halogen, oxo,hydroxy, lower alkyl, lower alkoxy, lower alkanoyloxy,cyclo(lower)alkyl, cyclo(lower)alkyloxy, aryl, aryloxy, heterocyclicgroup or hetrocyclic-oxy group; lower alkoxy; lower alkanoyloxy;cyclo(lower)alkyl; cyclo(lower)alkyloxy; aryl; aryloxy; heterocyclicgroup; heterocyclic-oxy group.

By combining an anti-tumor agent and a fatty acid derivative of formula(I), the effect of the anti-tumor agent is augmented and/or the adverseside effect of the anti-tumor agent is well suppressed.

In another aspect of the invention, there is provided a pharmaceuticalcomposition comprising:

(a) a pharmaceutically effective amount of an anti-tumor agent selectedfrom the group consisting of an alkylating agent, an antimetabolite, anantibiotic, a plant alkaloid, a molecular targeting drug, a hormone, aplatinum complex, an antisense, an antibody and RNAi and(b) a pharmaceutically effective amount of a fatty acid derivativerepresented by the formula (I) in association with a pharmaceuticallysuitable excipient.

According to the present invention, the composition comprising the twocomponents may be formulated in a single dosage unit that comprises bothof components (a) and (b) or separate dosage units that comprisecomponents (a) and (b) separately.

Further, the present invention provides a method for treating a tumor,which comprises administering a combination of:

(a) a pharmaceutically effective amount of an anti-tumor agent selectedfrom the group consisting of an alkylating agent, an antimetabolite, anantibiotic, a plant alkaloid, a molecular targeting drug, a hormone, aplatinum complex, an antisense, an antibody and RNAi and(b) a pharmaceutically effective amount of a fatty acid derivativerepresented by the formula (I) to a subject in need thereof.

According to the present invention, the components (a) and (b) may beadministered simultaneously, separately or sequentially.

Furthermore, the present invention provides a composition for treating atoxic side effect such as gastrointestinal damage including mucositisinduced by an anti-tumor agent in a mammalian subject, which comprises apharmaceutically effective amount of a fatty acid derivative representedby the formula (I), wherein the subject to be treated is receiving theanti-tumor agent that is selected from the group consisting of analkylating agent, an antimetabolite, an antibiotic, a plant alkaloid, amolecular targeting drug, a hormone, a platinum complex, an antisense,an antibody and RNAi.

Still further, the present invention also provides a composition fortreating mucositis such as stomatitis in a mammalian subject thatcomprises a pharmaceutically effective amount of a fatty acid derivativerepresented by the formula (I).

DETAILED DESCRIPTION OF THE INVENTION (a) Anti-Tumor Agent

Anti-tumor agent mentioned in the present invention is selected from thegroup consisting of an alkylating agent, an antimetabolite, anantibiotic, a plant alkaloid, a molecular targeting drug, a hormone, aplatinum complex, an antisense, an antibody and RNAi.

Examples of anti-tumor agents are alkylating agents such ascyclophosphamide and buslfan; antimetabolites such as methotrexate,6-mercaptopurine (6-MP), azathioprine, fluorouracil (5-FU), tegafur andcytosine arabinoside (ara-C); antibiotics such as bleomycin, mitomycinC, daunorubicin, adriamycin and actinomycin D; plant alkaloids such asvincristine, vinblastine, vindesine, paclitaxel, docetaxel, etoposideand irinotecan; molecular targeting drugs such as imatinib, gefinitib,erlotinib, sorafenib, sunitinib, trastuzumab, rituximab,gemtuzumab-ozogamicin, bevacizumab and cetuximab; hormones such asprednisolone, diethylstilbestrol and tamoxifen; platinum complexes suchas cisplatin, carboplatin and oxaliplatin; antisenses such as bcl-2antisense such as G3139, hsp27 antisense such as OGX427, XIAP antisensesuch as AEG35156, PKC-alpha antisense such as LY900003, hypoxia-inducedfactor antisense such as EZN-2968; antibodies such as CD20 antibody suchas Rituximab, Her2 antibody such as Trastuzumab, VEGF antibody such asBevacizumab, EGFR antibody such as Cetuximab: RNAi such as RNAi targetedRibonucleotide reductase such as CALAA-01. Preferable examples ofanti-tumor agents include 5-FU, tegafur and cisplatin.

(b) Fatty Acid Derivative

The nomenclature of the fatty acid derivative used herein is based onthe numbering system of the prostanoic acid represented in the aboveformula (A).

The formula (A) shows a basic skeleton of the C-20 carbon atoms, but thepresent invention is not limited to those having the same number ofcarbon atoms. In the formula (A), the numbering of the carbon atomswhich constitute the basic skeleton of the PG compounds starts at thecarboxylic acid (numbered 1), and carbon atoms in the α-chain arenumbered 2 to 7 towards the five-membered ring, those in the ring are 8to 12, and those in the ω-chain are 13 to 20. When the number of carbonatoms is decreased in the α-chain, the number is deleted in the orderstarting from position 2; and when the number of carbon atoms isincreased in the α-chain, compounds are named as substitution compoundshaving respective substituents at position 2 in place of the carboxygroup (C-1). Similarly, when the number of carbon atoms is decreased inthe ω-chain, the number is deleted in the order starting from position20; and when the number of carbon atoms is increased in the ω-chain, thecarbon atoms beyond position 20 are named as substituents.Stereochemistry of the compounds is the same as that of the aboveformula (A) unless otherwise specified.

In general, each of the terms PGD, PGE and PGF represents a PG compoundhaving hydroxy groups at positions 9 and/or 11, but in the presentspecification, these terms also include those having substituents otherthan the hydroxy group at positions 9 and/or 11. Such compounds arereferred to as 9-dehydroxy-9-substituted-PG compounds or11-dehydroxy-11-substituted-PG compounds. A PG compound having hydrogenin place of the hydroxy group is simply named as 9- or 11-deoxy-PGcompound.

As stated above, the nomenclature of the PG compounds is based on theprostanoic acid skeleton. However, in case the compound has a similarpartial structure as a prostaglandin, the abbreviation of “PG” may beused. Thus, a PG compound of which α-chain is extended by two carbonatoms, that is, having 9 carbon atoms in the α-chain is named as2-decarboxy-2-(2-carboxyethyl)-PG compound. Similarly, a PG compoundhaving 11 carbon atoms in the α-chain is named as2-decarboxy-2-(4-carboxybutyl)-PG compound. Further, a PG compound ofwhich ω-chain is extended by two carbon atoms, that is, having 10 carbonatoms in the ω-chain is named as 20-ethyl-PG compound. These compounds,however, may also be named according to the IUPAC nomenclatures.

Examples of the analogs (including substituted derivatives) orderivatives include a PG compound of which carboxy group at the end ofthe α-chain is esterified; a compound of which α-chain is extended;physiologically acceptable salt thereof; a compound having a double bondat 2-3 position or a triple bond at position 5-6, a compound havingsubstituent(s) at position 3, 5, 6, 16, 17, 18, 19 and/or 20; and acompound having lower alkyl or a hydroxy (lower) alkyl group at position9 and/or 11 in place of the hydroxy group.

According to the present invention, preferred substituents at positions3, 17, 18 and/or 19 include alkyl having 1-4 carbon atoms, especiallymethyl and ethyl. Preferred substituents at position 16 include loweralkyl such as methyl and ethyl, hydroxy, halogen atoms such as chlorineand fluorine, and aryloxy such as trifluoromethylphenoxy. Preferredsubstituents at position 17 include lower alkyl such as methyl andethyl, hydroxy, halogen atoms such as chlorine and fluorine, aryloxysuch as trifluoromethylphenoxy. Preferred substituents at position 20include saturated or unsaturated lower alkyl such as C1-4 alkyl, loweralkoxy such as C1-4 alkoxy, and lower alkoxy alkyl such as C1-4alkoxy-C1-4 alkyl. Preferred substituents at position 5 include halogenatoms such as chlorine and fluorine. Preferred substituents at position6 include an oxo group forming a carbonyl group. Stereochemistry of PGshaving hydroxy, lower alkyl or hydroxy(lower)alkyl substituent atposition 9 and/or 11 may be α, β or a mixture thereof.

Further, the above analogs or derivatives may be compounds having analkoxy, cycloalkyl, cycloalkyloxy, phenoxy or phenyl group at the end ofthe ω-chain where the chain is shorter than the primary PGs.

The fatty acid derivative used in the present invention is representedby the formula (I):

wherein L, M and N are hydrogen, hydroxy, halogen, lower alkyl,hydroxy(lower)alkyl, lower alkanoyloxy or oxo, wherein at least one of Land M is a group other than hydrogen, and the five-membered ring mayhave at least one double bond;

A is —CH₃, or —CH₂OH, —COCH₂OH, —COOH or a functional derivativethereof;

B is single bond, —CH₂—CH₂—, —CH═CH—, —C≡C—, —CH₂—CH₂—CH₂—, —CH═CH—CH₂—,—CH₂—CH═CH—, —C≡C—CH₂— or —CH₂—C≡C—;

Z is

or single bond

wherein R₄ and R₅ are hydrogen, hydroxy, halogen, lower alkyl, loweralkoxy or hydroxy(lower)alkyl, wherein R₄ and R₅ are not hydroxy andlower alkoxy at the same time;

R₁ is a saturated or unsaturated bivalent lower or medium aliphatichydrocarbon residue, which is unsubstituted or substituted with halogen,alkyl, hydroxy, oxo, aryl or heterocyclic group, and at least one ofcarbon atom in the aliphatic hydrocarbon is optionally substituted byoxygen, nitrogen or sulfur; and

Ra is a saturated or unsaturated lower or medium aliphatic hydrocarbonresidue, which is unsubstituted or substituted with halogen, oxo,hydroxy, lower alkyl, lower alkoxy, lower alkanoyloxy,cyclo(lower)alkyl, cyclo(lower)alkyloxy, aryl, aryloxy, heterocyclicgroup or hetrocyclic-oxy group; lower alkoxy; lower alkanoyloxy;cyclo(lower)alkyl; cyclo(lower)alkyloxy; aryl; aryloxy; heterocyclicgroup; heterocyclic-oxy group.

A preferred compound used in the present invention is represented by theformula (II):

wherein L and M are hydrogen atom, hydroxy, halogen, lower alkyl,hydroxy(lower)alkyl, lower alkanoyloxy or oxo, wherein at least one of Land M is a group other than hydrogen, and the five-membered ring mayhave one or more double bonds;

A is —CH₃, or —CH₂OH, —COCH₂OH, —COOH or a functional derivativethereof;

B is single bond, —CH₂—CH₂—, —CH═CH—, —C≡C—, —CH₂—CH₂—CH₂—, —CH═CH—CH₂—,—CH₂—CH═CH—, —C≡C—CH₂— or —CH₂—C≡C—;

Z is

or single bond

wherein R₄ and R₅ are hydrogen, hydroxy, halogen, lower alkyl, loweralkoxy or hydroxy(lower)alkyl, wherein R₄ and R₅ are not hydroxy andlower alkoxy at the same time;

X₁ and X₂ are hydrogen, lower alkyl, or halogen;

R₁ is a saturated or unsaturated bivalent lower or medium aliphatichydrocarbon residue, which is unsubstituted or substituted with halogen,alkyl, hydroxy, oxo, aryl or heterocyclic group, and at least one ofcarbon atom in the aliphatic hydrocarbon is optionally substituted byoxygen, nitrogen or sulfur;

R₂ is a single bond or lower alkylene; and

R₃ is lower alkyl, lower alkoxy, lower alkanoyloxy, cyclo(lower)alkyl,cyclo(lower)alkyloxy, aryl, aryloxy, heterocyclic group orheterocyclic-oxy group.

In the above formula, the term “unsaturated” in the definitions for R₁and Ra is intended to include at least one or more double bonds and/ortriple bonds that are isolatedly, separately or serially present betweencarbon atoms of the main and/or side chains. According to the usualnomenclature, an unsaturated bond between two serial positions isrepresented by denoting the lower number of the two positions, and anunsaturated bond between two distal positions is represented by denotingboth of the positions.

The term “lower or medium aliphatic hydrocarbon” refers to a straight orbranched chain hydrocarbon group having 1 to 14 carbon atoms (for a sidechain, 1 to 3 carbon atoms are preferable) and preferably 1 to 10,especially 1 to 8 carbon atoms.

The term “halogen atom” covers fluorine, chlorine, bromine and iodine.

The term “lower” throughout the specification is intended to include agroup having 1 to 6 carbon atoms unless otherwise specified.

The term “lower alkyl” refers to a straight or branched chain saturatedhydrocarbon group containing 1 to 6 carbon atoms and includes, forexample, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl,pentyl and hexyl.

The term “lower alkylene” refers to a straight or branched chainbivalent saturated hydrocarbon group containing 1 to 6 carbon atoms andincludes, for example, methylene, ethylene, propylene, isopropylene,butylene, isobutylene, t-butylene, pentylene and hexylene.

The term “lower alkoxy” refers to a group of lower alkyl-O—, whereinlower alkyl is as defined above.

The term “hydroxy(lower)alkyl” refers to a lower alkyl as defined abovewhich is substituted with at least one hydroxy group such ashydroxymethyl, 1-hydroxyethyl, 2-hydroxyethyl and1-methyl-1-hydroxyethyl.

The term “lower alkanoyloxy” refers to a group represented by theformula RCO—O—, wherein RCO— is an acyl group formed by oxidation of alower alkyl group as defined above, such as acetyl.

The term “cyclo(lower)alkyl” refers to a cyclic group formed bycyclization of a lower alkyl group as defined above but contains threeor more carbon atoms, and includes, for example, cyclopropyl,cyclobutyl, cyclopentyl and cyclohexyl.

The term “cyclo(lower)alkyloxy” refers to the group ofcyclo(lower)alkyl-O—, wherein cyclo(lower)alkyl is as defined above.

The term “aryl” may include unsubstituted or substituted aromatichydrocarbon rings (preferably monocyclic groups), for example, phenyl,tolyl, xylyl. Examples of the substituents are halogen atom andhalo(lower)alkyl, wherein halogen atom and lower alkyl are as definedabove.

The term “aryloxy” refers to a group represented by the formula ArO—,wherein Ar is aryl as defined above.

The term “heterocyclic group” may include mono- to tri-cyclic,preferably monocyclic heterocyclic group which is 5 to 14, preferably 5to 10 membered ring having optionally substituted carbon atom and 1 to4, preferably 1 to 3 of 1 or 2 type of hetero atoms selected fromnitrogen atom, oxygen atom and sulfur atom. Examples of the heterocyclicgroup include furyl, thienyl, pyrrolyl, oxazolyl, isoxazolyl, thiazolyl,isothiazolyl, imidazolyl, pyrazolyl, furazanyl, pyranyl, pyridyl,pyridazinyl, pyrimidyl, pyrazinyl, 2-pyrrolinyl, pyrrolidinyl,2-imidazolinyl, imidazolidinyl, 2-pyrazolinyl, pyrazolidinyl,piperidino, piperazinyl, morpholino, indolyl, benzothienyl, quinolyl,isoquinolyl, purinyl, quinazolinyl, carbazolyl, acridinyl,phenanthridinyl, benzimidazolyl, benzimidazolinyl, benzothiazolyl,phenothiazinyl. Examples of the substituent in this case includehalogen, and halogen substituted lower alkyl group, wherein halogen atomand lower alkyl group are as described above.

The term “heterocyclic-oxy group” means a group represented by theformula HcO—, wherein Hc is a heterocyclic group as described above.

The term “functional derivative” includes salts (preferablypharmaceutically acceptable salts), ethers, esters and amides.

Suitable “pharmaceutically acceptable salts” include conventionally usednon-toxic salts, for example a salt with an inorganic base such as analkali metal salt (such as sodium salt and potassium salt), an alkalineearth metal salt (such as calcium salt and magnesium salt), an ammoniumsalt; or a salt with an organic base, for example, an amine salt (suchas methylamine salt, dimethylamine salt, cyclohexylamine salt,benzylamine salt, piperidine salt, ethylenediamine salt, ethanolaminesalt, diethanolamine salt, triethanolamine salt,tris(hydroxymethylamino)ethane salt, monomethyl-monoethanolamine salt,procaine salt and caffeine salt), a basic amino acid salt (such asarginine salt and lysine salt), tetraalkyl ammonium salt and the like.These salts may be prepared by a conventional process, for example fromthe corresponding acid and base or by salt interchange.

Examples of the ethers include alkyl ethers, for example, lower alkylethers such as methyl ether, ethyl ether, propyl ether, isopropyl ether,butyl ether, isobutyl ether, t-butyl ether, pentyl ether and1-cyclopropyl ethyl ether; and medium or higher alkyl ethers such asoctyl ether, diethylhexyl ether, lauryl ether and cetyl ether;unsaturated ethers such as oleyl ether and linolenyl ether; loweralkenyl ethers such as vinyl ether, allyl ether; lower alkynyl etherssuch as ethynyl ether and propynyl ether; hydroxy(lower)alkyl etherssuch as hydroxyethyl ether and hydroxyisopropyl ether; lower alkoxy(lower)alkyl ethers such as methoxymethyl ether and 1-methoxyethylether; optionally substituted aryl ethers such as phenyl ether, tosylether, t-butylphenyl ether, salicyl ether, 3,4-di-methoxyphenyl etherand benzamidophenyl ether; and aryl(lower)alkyl ethers such as benzylether, trityl ether and benzhydryl ether.

Examples of the esters include aliphatic esters, for example, loweralkyl esters such as methyl ester, ethyl ester, propyl ester, isopropylester, butyl ester, isobutyl ester, t-butyl ester, pentyl ester and1-cyclopropylethyl ester; lower alkenyl esters such as vinyl ester andallyl ester; lower alkynyl esters such as ethynyl ester and propynylester; hydroxy(lower)alkyl ester such as hydroxyethyl ester; loweralkoxy (lower) alkyl esters such as methoxymethyl ester and1-methoxyethyl ester; and optionally substituted aryl esters such as,for example, phenyl ester, tolyl ester, t-butylphenyl ester, salicylester, 3,4-di-methoxyphenyl ester and benzamidophenyl ester; andaryl(lower)alkyl ester such as benzyl ester, trityl ester and benzhydrylester.

The amide of A mean a group represented by the formula —CONR′R″, whereineach of R′ and R″ is hydrogen, lower alkyl, aryl, alkyl- oraryl-sulfonyl, lower alkenyl and lower alkynyl, and include for examplelower alkyl amides such as methylamide, ethylamide, dimethylamide anddiethylamide; arylamides such as anilide and toluidide; and alkyl- oraryl-sulfonylamides such as methylsulfonylamide, ethylsulfonyl-amide andtolylsulfonylamide.

Preferred examples of L and M include hydrogen, hydroxy and oxo, andespecially, M is hydroxy or hydrogen and L is oxo.

Preferred example of A is —COOH, its pharmaceutically acceptable salt,ester or amide thereof.

Preferred example of X₁ and X₂ are both being halogen atoms, and morepreferably, fluorine atoms, so called 16,16-difluoro type.

Preferred R₁ is a hydrocarbon residue containing 1-10 carbon atoms,preferably 6-10 carbon atoms. Further, at least one carbon atom in thealiphatic hydrocarbon is optionally substituted by oxygen, nitrogen orsulfur. Examples of R₁ include, for example, the following groups:

—CH₂—CH₂—CH₂—CH₂—CH₂—CH₂—,

—CH₂—CH═CH—CH₂—CH₂—CH₂—,

—CH₂—CH₂—CH₂—CH₂—CH═CH—,

—CH₂—C≡C—CH₂—CH₂—CH₂—,

—CH₂—CH₂—CH₂—CH₂—O—CH₂—,

—CH₂—CH═CH—CH₂—O—CH₂—,

—CH₂—C≡C—CH₂—O—CH₂—,

—CH₂—CH₂—CH₂—CH₂—CH₂—CH₂—CH₂—,

—CH₂—CH═CH—CH₂—CH₂—CH₂—CH₂—,

—CH₂—CH₂—CH₂—CH₂—CH₂—CH═CH—,

—CH₂—C≡C—CH₂—CH₂—CH₂—CH₂—,

—CH₂—CH₂—CH₂—CH₂—CH₂—CH(CH₃)—CH₂—,

—CH₂—CH₂—CH₂—CH₂—CH(CH₃)—CH₂—,

—CH₂—CH₂—CH₂—CH₂—CH₂—CH₂—CH₂—CH₂—,

—CH₂—CH═CH—CH₂—CH₂—CH₂—CH₂—CH₂—,

—CH₂—CH₂—CH₂—CH₂—CH₂—CH₂—CH═CH—,

—CH₂—C≡C—CH₂—CH₂—CH₂—CH₂—CH₂—, and

—CH₂—CH₂—CH₂—CH₂—CH₂—CH₂—CH(CH₃)—CH₂—.

Preferred Ra is a hydrocarbon containing 1-10 carbon atoms, morepreferably, 1-8 carbon atoms. Ra may have one or two side chains havingone carbon atom.

Preferable compounds include Ra is substituted by halogen and/or Z isC═O in the formula (I), or one of X1 and X2 is substituted by halogenand/or Z is C═O in the formula (II).

Example of the preferred embodiment is a(−)-7-[(2R,4aR,5R,7aR)-2-(1,1-Difluoropentyl)-2-hydroxy-6-oxooctahydrocyclopenta[b]pyran-5-yl]heptanoicacid,(−)-7-{(2R,4aR,5R,7aR)-2-[(3S)-1,1-difluoro-3-methylpentyl]-2-hydroxy-6-oxooctahydrocyclopenta[b]pyran-5-yl}heptanoicacid and(−)-7-[(1R,2R)-2-(4,4-difluoro-3-oxooctyl)-5-oxocyclopentyl]heptanoicacid or its functional derivative thereof.

The configuration of the ring and the α- and/or ωchains in the aboveformula (I) and (II) may be the same as or different from that of theprimary PGs. However, the present invention also includes a mixture of acompound having a primary type configuration and a compound of anon-primary type configuration.

In the present invention, the fatty acid derivative which is dihydrobetween 13 and 14, and keto(═O) at 15 position may be in theketo-hemiacetal equilibrium by formation of a hemiacetal between hydroxyat position 11 and keto at position 15.

For example, it has been revealed that when both of X₁ and X₂ arehalogen atoms, especially, fluorine atoms, the compound contains atautomeric isomer, bicyclic compound.

If such tautomeric isomers as above are present, the proportion of bothtautomeric isomers varies with the structure of the rest of the moleculeor the kind of the substituent present. Sometimes one isomer maypredominantly be present in comparison with the other. However, it is tobe appreciated that the present invention includes both isomers.

Further, the fatty acid derivatives used in the invention include thebicyclic compound and analogs or derivatives thereof.

The bicyclic compound is represented by the formula (III)

wherein, A is —CH₃, or —CH₂OH, —COCH₂OH, —COOH or a functionalderivative thereof;

X₁′ and X₂′ are hydrogen, lower alkyl, or halogen;

Y is

wherein R₄′ and R₅′ are hydrogen, hydroxy, halogen, lower alkyl, loweralkoxy or hydroxy(lower)alkyl, wherein R₄′ and R₅′ are not hydroxy andlower alkoxy at the same time.

R₁ is a saturated or unsaturated divalent lower or medium aliphatichydrocarbon residue, which is unsubstituted or substituted with halogen,alkyl, hydroxy, oxo, aryl or heterocyclic group, and at least one ofcarbon atom in the aliphatic hydrocarbon is optionally substituted byoxygen, nitrogen or sulfur; and

R₂′ is a saturated or unsaturated lower or medium aliphatic hydrocarbonresidue, which is unsubstituted or substituted with halogen, oxo,hydroxy, lower alkyl, lower alkoxy, lower alkanoyloxy,cyclo(lower)alkyl, cyclo(lower)alkyloxy, aryl, aryloxy, heterocyclicgroup or hetrocyclic-oxy group; lower alkoxy; lower alkanoyloxy;cyclo(lower)alkyl; cyclo(lower)alkyloxy; aryl; aryloxy; heterocyclicgroup; heterocyclic-oxy group.

R₃′ is hydrogen, lower alkyl, cyclo(lower)alkyl, aryl or heterocyclicgroup.

Furthermore, while the compounds used in the invention may berepresented by a formula or name based on keto-type regardless of thepresence or absence of the isomers, it is to be noted that suchstructure or name does not intend to exclude the hemiacetal typecompound.

In the present invention, any of isomers such as the individualtautomeric isomers, the mixture thereof, or optical isomers, the mixturethereof, a racemic mixture, and other steric isomers may be used in thesame purpose.

Some of the compounds used in the present invention may be prepared bythe method disclosed in U.S. Pat. Nos. 5,073,569, 5,166,174, 5,221,763,5,212,324, 5,739,161 and 6,242,485 (these cited references are hereinincorporated by reference).

Pharmaceutically Suitable Excipient

According to the invention, each of the components of the combinationmay be formulated in any form together or separately to give apharmaceutical composition. The pharmaceutically suitable excipient maybe, therefore, selected depending on the desired form of thecomposition. According to the invention, “pharmaceutically suitableexcipient” means an inert substance, which is suitable for the form,combined with the active ingredient of the invention.

For example, solid composition for oral administration of the presentinvention may include tablets, capsules, pills, powders, granules andthe like. In such a solid composition, one or more active ingredientsmay be mixed with at least one inactive diluent, for example, lactose,mannitol, glucose, hydroxypropyl cellulose, microcrystalline cellulose,starch, polyvinyl pyrrolidone, magnesium aluminate metasilicate and thelike. According to the usual work-up, the composition may containadditives other than inactive diluent, for example, lubricant such asmagnesium stearate; disintegrant such as fibrous calcium gluconate;stabilizer such as cyclodextrin, for example, α,β- or γ-cyclodextrin;etherified cyclodextrin such as dimethyl-α-, dimethyl-β-, trimethyl-β-,or hydroxypropyl-β-cyclodextrin; branched cyclodextrin such asglucosyl-, maltosyl-cyclodextrin; formylated cyclodextrin, cyclodextrincontaining sulfur; phospholipid and the like. When the abovecyclodextrins are used, an inclusion compound with cyclodextrins may besometimes formed to enhance stability. Alternatively, phospholipid maybe sometimes used to form a liposome, resulting in enhanced stability.

Tablets or pills may be coated with film soluble in the stomach orintestine such as sugar, gelatin, hydroxypropyl cellulose, orhydroxypropylmethyl cellulose phthalate as needed. Further, they may beformed as capsules with absorbable substances such as gelatins.Preferably, the composition is formulated in a soft gelatin capsule withliquid contents of the fatty acid derivative and a medium chain fattyacid triglyceride. Examples of the medium chain fatty acid triglycerideused in the present invention include a triglyceride of a saturated orunsaturated fatty acid having 6-14 carbon atoms which may have abranched chain. A preferred fatty acid is a straight chain saturatedfatty acid, for example caproic acid (C6), caprylic acid (C8), capricacid (C10), lauric acid (C12) and myristic acid (C14). In addition, twoor more medium chain fatty acid triglycerides may be used incombination. Further suitable excipients are disclosed in WO 01/27099.

A liquid composition for oral administration may be pharmaceuticallyacceptable emulsion, solution, suspension, syrup, or elixir, as well asgenerally used inactive diluent. Such composition may contain, inaddition to the inactive diluent, adjuvant such as lubricant andsuspension, sweetening agent, flavoring agent, preservatives,solubilizers, anti-oxidants and the like. The details of the additivesmay be selected from those described in any general textbooks in thepharmaceutical field. Such liquid compositions may be directly enclosedin soft capsules. Solutions for parenteral administration, for example,suppository, enema and the like according to the present inventioninclude sterile, aqueous or non-aqueous solution, suspension, emulsion,detergent and the like. The aqueous solution and suspension includes,for example, distilled water, physiological saline and Ringer'ssolution.

The non-aqueous solution and suspension include, for example, propyleneglycol, polyethylene glycol, fatty acid triglyceride, and vegetable oilsuch as olive oil, alcohols such as ethanol, polysorbate and the like.Such composition may contain adjuvants such as preservatives, wettingagent, emulsifier, dispersant, anti-oxidants and the like.

Examples of the injectable compositions of the present invention forparenteral administration include sterile aqueous or non-aqueoussolutions, suspensions and emulsions. Diluents for the aqueous solutionor suspension may include, for example, distilled water for injection,physiological saline and Ringer's solution.

Non-aqueous diluents for solution and suspension may include, forexample, propylene glycol, polyethylene glycol, vegetable oils such asolive oil, alcohols such as ethanol and polysorbate. The composition mayfurther comprise additives such as preservatives, wetting agents,emulsifying agents, dispersing agents and the like. They may besterilized by filtration through, e.g. a bacteria-retaining filter,compounding with a sterilizer, or by means of gas or radioisotopeirradiation sterilization. The injectable composition may also beprovided as a sterilized powder composition to be dissolved in asterilized solvent for injection before use.

The composition of the present invention may be in the form of sprayingcomposition, which may be prepared according to a known method.

The composition of the present invention may be in the form ofintranasal preparation. Example of the intranasal preparations may beaqueous or oily solutions, suspensions or emulsions comprising one ormore active ingredient. For the administration of an active ingredientby inhalation, the composition of the present invention may be in theform of suspension, solution or emulsion which can provide aerosol or inthe form of powder suitable for dry powder inhalation. The compositionfor inhalational administration may further comprise a conventionallyused propellant.

Example of the external agent includes all the external preparationsused in the fields of dermatology and otolaryngology, which includesointment, cream, liquids, lotion, patch and spray.

Another form of the composition of the present invention is suppositoryor pessary, which may be prepared by mixing active ingredients into aconventional base such as cacao butter that softens at body temperature,and nonionic surfactants having suitable softening temperatures may beused to improve absorbability.

According to the method of the invention, the composition of the presentinvention can be administered systemically or locally by means of oralor parenteral administration, including a suppository, enema and thelike. Single or multiple compositions may be administered to achieve thedesired dose.

The expression of “administering the combination” or “combination isadministered” used herein means both components are administered to asubject simultaneously in the form of a single entity or dosage, or bothcomponents are administered to a patient as separate entities eithersimultaneously or sequentially with no specific time limits, whereinsuch administration provides therapeutically effective levels of the twocomponents in the body, preferably at the same time.

According to the present invention, tumor in a mammalian subject may betreated by the instant invention by administering the combination of thepresent invention. The mammalian subject may be any subject including ahuman patient. The composition may be applied systemically or topically.Usually, the compound may be administered by oral administration,intranasal administration, inhalational administration, intravenousinjection (including infusion), subcutaneous injection, intra rectaladministration, intra vaginal administration, transdermal administrationas well as it may be an external agent including liquid, ointment, pasteor patch and the like.

The dose of each component may vary depending on the strain of theanimal, age, body weight, symptom to be treated, desired therapeuticeffect, administration route, term of treatment and the like. Asatisfactory effect can be obtained by systemic administration 1-4 timesper day or continuous administration of the combination. The amount ofcomponent (a) of the combination may be, for example, about 0.1 to about100 mg/kg/day, preferably about 0.5 to about 30 mg/kg/day, for tegafur;0.1 to about 100 mg/kg/day, preferably about 10 to about 40 mg/kg/dayfor 5-FU; 0.1 to 100 mg/kg/day, preferably 5 to 30 mg/kg/day forcisplatin. The amount of component (b) or a fatty acid derivative offormula (I) may be about 0.00001-500 mg/kg per day, more preferably0.001-1000 μg/kg per day, and especially 0.01-100 μg/kg per day. Thetopical formulation of a fatty acid derivative of formula (I) may be0.000001-10.0%, more preferably 0.00001-5.0% by weight base on the totalamount of the composition.

The combination of the present invention can be administered in a singledose or in 2 to 4 divided doses per day. When in the form of aninjectable solution for, for example, intravenous injection, thecomposition, which, if necessary, may be diluted with a physiologicalsaline or injectable glucose solution, can be gradually administered toan adult human subject over 5 minutes or longer. When in the form of asuppository, the composition is administered to an adult human subjectonce or twice a day at an interval of 6 to 12 hours by insertion intothe rectum.

Further, damages induced by an anti-tumor agent in a mammalian subjectmay be treated by administering the composition comprising a fatty acidderivative of formula (I). In this embodiment, the compositioncomprising the fatty acid derivative of formula (I) may be prepared andadministered in the same manner as discussed above.

The term “treatment” or “treating” used herein includes any means ofcontrol such as prevention, care, relief of the condition, attenuationof the condition and arrest of progression.

The types of tumors to be treated by the combination of the presentinvention are not limited and may be, for example, head and neckcancers, gastrointestinal cancers such as esophageal cancer, gastriccancer, colon cancer, rectal cancer (cancer of the large intestine) andpancreatic cancer, liver cancer, gallbladder/biliary cancer, lungcancer, breast cancer, vesical cancer, prostate cancer, uterine cancer,pharyngeal cancer, renal cancer, ovarian cancer, etc. In particular, aremarkable effect can be expected toward gastrointestinal cancers.

According to the present invention, the antitumor effect of ananti-tumor agent as an active ingredient can be significantlystrengthened without notably increasing the toxicity of the same.

In addition, according to the present invention, the fatty acidderivatives are useful for reducing or preventing toxic side effectespecially, gastrointestinal damage induced by the anti-tumor agent. Thegastrointestinal damages induced by an anti-tumor agent may be mucositissuch as stomatitis, enteritis, gastrointestinal ulcer, pancreatitis,heaptic and biliary disorders.

The pharmaceutical composition of the present invention may furthercontain other pharmacological ingredients as far as they do notcontradict the purpose of the present invention.

Further details of the present invention will follow with reference totest example, which, however, is not intended to limit the presentinvention.

Example 1 Effects of Compound A Against 5-FU Induced Toxicity Methods

After 1 week of acclimatization period, the experiment started (Day 0).Compound A((−)-7-{(2R,4aR,5R,7aR)-2-[(3S)-1,1-difluoro-3-methylpentyl]-2-hydroxy-6-oxooctahydrocyclopenta[b]pyran-5-yl}heptanoicacid) (3, 10, 30 μg/kg) or vehicle was administered orally once dailyfor 5 days from Day 0 to 4 (Schedule 1).

In other dosing schedule group, Compound A (30 μg/kg) was administeredorally once daily from Day 4 to Day 6 (Schedule 2).

5-FU (50 mg/kg) was administered intraperitoneally once daily for 4 daysfrom Day 1 to 4. On Day 1, 2, 3, and 4, 5-FU was administeredimmediately after administration of Compound A or vehicle. During theexperiment period (Day 0-7), animals were weighed every day. On Day 7,the animals were anesthetized by isofluran. Ileum was excised and fixedin 10% formalin. Paraffin-embedded sections were prepared and stainedwith H&E for histopathological evaluation of tissue damage. The tissuedamage was graded according to the following criteria:

0. No change,

1: slight,

2: mild,

3: moderate,

4: severe

The effect of each compound was evaluated using total score of tissuedamage.

Results

The total score of each treatment group is shown in the table below.Compound A decreased total scores at 10 or 30 μg/kg regardless of thedosing schedule. This suggests that Compound A is potent against thetoxicity, especially, gastrointestinal toxicity such as mucositisinduced by 5-FU.

No. of Dose animals Dosing Total Drugs (μg/kg) examined Schedule scoreNo treatment — 3 — 0.0 Vehicle — 3 1 10.3 Compound A 3 3 1 10.0 10 3 15.0 30 3 1 5.7 30 3 2 4.3

Example 2 Effects of Compound A on Stomatitis Methods

Male Golden Syrian hamsters (5 weeks old) were used. After 1 weekacclimatization period, the hamsters were administered intraperitoneallywith 60 mg/kg 5-fluorouracil (5-FU) (Day 1). 5-FU administration wasrepeated again on Day 2. On Day 4, the cheek pouch mucosa of thehamsters is mechanically irritated under anesthesia by superficialscratching with the tip of an 18-gauge needle to produce transienterythema. On Day 8 and 10, the same scratching procedure was conductedand 5-FU administration was done. The Compound A at the doses of 24μg/site or vehicle was topically applied to the cheek pouches from Day 1to Day 14. During the treatment, the cheek pouch mucosa wasmacroscopically observed and the buccal lesion was scored according tothe following criteria (stomatitis score):

-   -   0: Normal mucosa    -   1: Erythema was observed    -   2: Severe erythema was observed    -   3: Severe erythema and formation of ulcers in one or more places        were observed. Cumulative size of the ulcers involves ˜25% of        the pouch mucosa. Pseudomembrane formation was evident.    -   4: Severe erythema and formation of ulcers were observed.        Cumulative size of the ulcers involved about half of the pouch        mucosa. Loss of mucosal pliability.    -   5: diffuse, extensive ulceration. Loss of mucosal pliability.        Pouch could be only partially extracted from mouth.

Severity of stomatitis was evaluated using the mean of scores pertreatment group.

Results

Compared to vehicle control group, Compound A improved stomatitisaggravated by 5-FU treatment.

stomatitis score 5-EU on Day 14 Group treatment n (Mean ± SE) Notreatment No 4 0 Vehicle control Yes 4 1.25 ± 0.25  Compound A Yes 40.25 ± 0.25* 24 μg/site *p < 0.05 vs. vehicle control group (student'st-test)

What is claimed is:
 1. A method for treating mucositis in a mammaliansubject, which comprises administering a pharmaceutically effectiveamount of(−)-7-[(2R,4aR,5R,7aR)-2-(1,1-Difluoropentyl)-2-hydroxy-6-oxooctahydro-cyclopenta[b]pyran-5-yl]heptanoicacid or its functional derivative to the subject in need thereof.
 2. Themethod as described in claim 1, wherein the mucositis is stomatitis. 3.The method as described in claim 1, wherein the mucositis is oralmucositis.
 4. The method as described in claim 1, wherein the subject isreceiving an anti-tumor agent that is selected from the group consistingof an alkylating agent, an antimetabolite, an antibiotic, a plantalkaloid, a molecular targeting drug, a hormone, a platinum complex, anantisense, an antibody and RNAi, wherein the molecular targeting drug isselected from the group consisting of imatinib, gefinitib, erlotinib,sorafenib, sunitinib, trastuzumab, rituximab, gemtuzumab-ozogamicin,bevacizumab and cetuximab, the hormone is selected from group consistingof prednisolone, diethylstilbestrol and tamoxifen, the antisense isselected from the group consisting of bcl-2 antisense, hsp27 antisense,XIAP antisense, PKC-alpha antisense and hypoxia-induced factorantisense, the antibody is selected from the group consisting of CD20antibody, Her2 antibody, VEGF antibody and EGFR antibody, and the RNAiis RNAi targeted Ribonucleotide reductase.
 5. The method as described inclaim 4, wherein said anti-tumor agent is 5-FU or tegafur.
 6. The methodas described in claim 4, wherein said anti-tumor agent is cisplatin. 7.The method as described in claim 4, wherein the anti-tumor agent isselected from the group consisting of an alkylating agent, anantimetabolite, an antibiotic and a plant alkaloid.
 8. The method asdescribed in claim 4, wherein the mucositis is induced by the antitumoragent.